Regulating transformer



March 12, 1935. A. MEYERHANS l 1,993,794

REGULATING TRANSFORMER Filed Dec. 14, 1935 4 Sheets-Sheet 1 March 12, 1935. A. MEYERHANS REGULATING TRANSFORMER Filed DeG. 14, 1955 4 Sheets-Sheet 2 A. MEYERHANS REGULATING TRANSFORMER March 12, 1935. 1,993,794

Filed DSC. 14, 1933 4 Shees-Sheet 5 16T 40 2 s sa 2 March 12, 1935. A. MEYERHANS REGULATING TRANSFORMER Filed Deo. 14, 1955 4 Sheets-Sheet 4 )ver Patented Mar. l2., 1935 UNITED STATES PATENT OFFICE RE GULATIN G TRAN SFORMER August MeyerhansJtieden, Switzerland, assgnor to Aktiengesellschaft Brown, Boveri & Cie., Baden, Switzerland Application December` 14, 1933, Serial No. 702,271 In Germany December 17, 1932 13Claims. (Cl. 171-119) This invention relates to a new method and regulating transformer according to my invenapparatus for the continual regulation of electric tion. voltage, more particularly to an electric trans- Fig. '7 is a schematic cross sectional view taken former having coils of spiral configuration. in a plane perpendicular to the main axis of a An object of this invention resides in the promodification of an electric voltage transformer 5 vision of an apparatus for continually regulating according to my invention. electric voltage by means ofatransformer,where Figs. 8, 9, 10 and 11 diagrammatically show by the distribution of the ampere windings is relative positions of collectors and coils persymmetrcal at all voltages, that is, control containing to one transformer according to my inditions. vention. m

An object of this invention resides in the pro- Fig. 12 is an axial cross sectional view of an vision of a new method and design for continuelectric voltage regulating transformer according ally regulating electric voltage by means of a to my invention having no external sliding coriti'ansformer, whereby, even at a very wide range tacts.

l5 of control, the distribution of the ampere wind- Fig. 13 is an axial cross sectional view of an 15 ings is symmetrical also in the extreme control electric voltage regulating transformer according conditions. to my invention showing the transition of certain An object of this invention resides in the pro- Conductors through the magnet yOkeS in Darvision of a new method and design for continuiCllla.

ally regulating electric voltage by means of a Fig. 14 is a diagram of connections of a trans- 2o transformer of such design as to permit the use former aS per Figs. 12 and 13 built as three phase of well balanced sliding contacts assuring con- Current Voltage regulating transformer. stant contact pressure at all operating conditions. Fig- 15 iS an axial CrOSS Sectional view of a one An object of this invention resides in the procoil pair electric .voltage control transformer acvision of an electric voltage control transformer C01d1ng-i0 my lllilenton Showing the Control 25 permitting a quick and continual change over mechallslll 1n Partlular.. from one voltage' to no1-,heh Fig. 16 is a cross sectional view of the control Another object of my invention is the provision transformer illustrated by Fig. 15 and taken along of an electric voltage regulating transformer per- 11ne 15 1 5 0f Flg; 15-

initting a continual regulation of the electric volt- Flg- 17 1S an axial CYOSS Sjectlonal VleW through 30 age within very wide ranges and requiring only a m elePtflC Voltage regulatmg 'H 'aDSOImer havvery simple and inexpensive control mechanism. mg P rlmal'y and secfmdary C0115 {ntelSDfllSed and A further object of my invention is the pro showing the regulating contacts 1n detail.

vision of an electric voltage regulating trans Fig. 18 is an axial cross sectional v iew through former assuring all the before mentioned objects an elecmc Voltage tFansformer hafmlg Primary 35 and being light and requiring little Space. and secondary coils interspersed within one an- Further and other objects of the present im .other and showing a modification of this intert vention will be hereinafter set forth in the acspelsmg arangemen companying specification and claims and shown F 1g 19 1S a schem8't1-c showing of the wmng in the drawings which by way of illustration Of' tfransformer accodlllg tio Ilgll'dnd 18 40 e erring more par ic ar y o e awings: lsoh? Wh't f1 novgncolgr to be a preferred em Fig. 1 diagrammatically illustrates an example omnl daglilgs ve 1 of the many possibilities of reducing my invention t 2 Fig. 1 is a partial cross sectional view taken o practlce 1 and are the Secondary cons of t 1 1 t the electric voltage transformer while 3 is the 45 a'long the mam axis of ain elec no ".0 tage-regu a' primary coil. 4 and 5 are spirally coiled copper ing transformer according to iny invention.

n bands constituting the secondary coils, the copper Flgs- 2 3 and 4 are dlagrams of connectlon strips being separated by the insulating strips Fig. 5 is a cross Sectional view taken alvng the i and i'. s is the magnet core. The individual main aXiS 0f a mOdfled apparatus acrdng G0 secondary coils 1 and 2 are mounted to an elec- 50 my iIlVEDtiOIl and ShOWing in particular Certain trically insulating cylinder l0, for instance, by wiring features. means of electrically insulated bolts 11 which are Fig. 6 is a schematic cross sectional view taken radial with respect to cylinder l0. Such bolts in a plane perpendicular to the main axis and greatly increase the strength of the coils. Cylinalong line 6-6 of Fig. 1 of an electrical voltage der 10 together with`coils 1 and 2 may be arranged 55 to be revolved. This can be accomplished by providing a spur gear 12 cooperating with pinion 13. Pinion 13 can be operated at a remote point by manipulation of hand wheel 14 which is connected with pinion 13 by shafting 55. The brushes 16 are pressed to the conductors 4 and 5 by spring member 1'7 and are guided by the insulating strips 7 and 7. The brushes are held by the legs of the U-shaped part 18 and are axially movable. With this arrangement the reaction of the Contact pressure on the contact pieces is well counterbalanced. The current collected by brushes 16 is conducted by a flexible conductor 19 which permits a radial movement of the bow 18 when the spiral coils l and 2 are rotated. I can as well arrange the insulation cylinder to be stationary and the bow 18 with brushes 16 to be pulled around the spiral coils by way of the flexible conductor 19. Upon each revolution of the cylinder 10 or the brushes 16 one winding is added to or deducted from the number of secondary windings in operation and the voltage is changed accordingly. f

There can be any number of secondary coils designated by numerals 1 and 2 mounted to the cylinder 10. The secondary coils which are served by one pair of brushes 16 may be connected in parallel as is shown by the diagram of connections Fig. 2 and all pairs connected in series with each other. It is obvious that there is always the same number of windings in operation in all pairs of secondary coils and that the action is equally distributed over the whole length of the magnet core 8 as well as the primary coil 3. With one revolution of cylinder 10 or bow 18 and brushes 16 a great number of active secondary coils is added or deducted and a wide change of voltage can be obtained by a small movement of the regulating apparatus.

It is obvious that, due to these features, the apparatus is very compact and a great variety of operating conditions and a wide range of control can be obtained on a small space. The system according to my invention is, therefore, particularly useful for plants where space is scarce as, for instance, electric locomotives. In this application transformers according to my invention can be built as one phase transformers and used for directly feeding the motors supplying motive power.

If cylinder 10 is stationary and brushes 16 revolvable, a brush 20 for each pair of coils is necessary. If cylinder 10 is revolved together with the secondary coils, a slip ring 21 cooperating with brushes 22, which are connected to the secondary coils by conductors 23 and 24, must be provided. Conductor 25 connects the slip ring 21 with the outside. This is more particularly shown on Fig. 1. 26 and 27 are the terminals of the secondary coils. All the coils can also be connected in parallel as shown on Fig. 3 or both methods of connection can be combined.

Instead of connecting each pair of coils in parallel, the individual coils of one pair served by the same pair of collector brushes can be connected in series. This is illustrated by Fig. 4. 26 and 27 are the terminals of the secondary system. The current flows from terminal 26 consecutively through coil 1, brush 16', conductor 19', coil 2, brush 16", conductor 19 to terminal 27. In this case brushes 16 and 16 must be electrically insulated from one another. If the coils are stationary, collectors and brushes 20' and 20 must be provided. Of course, a plurality of pairs of coils can be provided, all individual coils being connected in series, or some of the coils in parallel and others in series. The serial connection oi' the secondary coils is particularly applicable when small currents and high tensions must be negotiated and a wide range of voltage regulation is desired.

Instead of mounting the secondary coils 1, 2 etc. on the outside of cylinder 10, they can be mounted to the inside as shown by Fig. 5. The secondary coils are stationary and the magnet core 8 arranged revolvably together with the contactors 18 carrying the brushes 16 and the conductor 28 electrically connecting all the brushes 16. 29 is a slip ring electrically connected with conductors 28 and revolving with core 8. Electric connection of the slip ring and terminal 27 is obtained by brush 20. The magnet yokes 30 are stationary and have openings for letting through the conductor 23 connecting the secondary coils and the terminal 26 and also the electric conductors 31 and 32 connecting the primary coil 3 which, in this case, is outside of the secondary coils and the terminals 33 and 34. This arrangement is preferable to one in which, for instance, the magnet core is stationary and the conductor 28 rotates within an annular slot around the axis of the device thereby generating eddy currents at each regulating operation.

In order to obtain an equal distribution of the eld along the whole circumference of the coils and to obtain an even voltage regulation around the whole circumference, it is advantageous to surround the transformer with an iron shell. To use involute laminae for the core as well as for the shell is of particular advantage. This is shown in Fig. 6 which is a schematic cross sectional view of a transformer according to my invention, the section being taken along line 6 6 of Fig. 1 and perpendicular to the main axis. 35

is the shell, 1 the spiral secondary coil, 3 the primary coil, and 8 the magnet core.

Fig. 7 schematically illustrates a modification of a transformer having eight magnet yokes 36 regularly distributed around the circumference of the transformer and connected by radial branches 87 with the magnet core 8; the other parts are arranged in the same way as shown in Figs. 1 and 6.

In order to eliminate the influence of the slight displacement of the magnetic field along the circumference of the regulating coil when current is conducted through parts of the coil only, it is advisable to stagger the position of the collectors 16 as well as the ends of the individual regulating coils 1, 2 etc. around the axis of the transformer and thus equally distribute the action of these parts over the whole device. This is diagrammatically illustrated in Figs. 8, 9, 10 and 11 wherein 16 indicates a pair of collector brushes pertaining to one pair of regulating coils, the solid lines 1 representing coil 1 of the pair of coils and the dotted lines coil 2 of the pair of coils. It will be noted that the position of the collectors 16 as well as the ends of the coils 1 and 2 are equally distributed around the circumference of the `device.

. In order to eliminate slip rings 21 or 29 which are necessary in the hitherto described embodiments of my invention, the invention can be carried out by an apparatus as illustrated by Figs. 12 and 13. 1' and 2' and 1" and 2" designate two pairs of regulating coils which are all wound in the same direction. 3' and 3" are the primary coils pertaining to secondary coils l', 2 and 1, 2", respectively. Each pair of regulating coils is provided with an individual iron core and yoke system 8', 30' and 8", 30" which are independent from one another.- 'Ihe direction of the magnet field in the individual iron systems is, therefore, opposite, as indicated by arrows 37 and 38. The collectors 16' andy 16" of the individual systems are connected by the bracket part 39 which is movable in annular slots 40 and 40" in the magnetic .yokes 30' and 30" and can be rotated around the axis 41 of the system. Thereby an equal number of regulating coilsare added or deducted at` each revolution of the electrically conducting bow 39. The regulated current flows from terminal 26 which is electrically and directly connected with the coils 1 and 2', therefrom through bow 39 and coils 1" and 2" and to the directly connected terminal 27 or in the reverse direction. Instead of revolving the bow 39 with collectors 16 and 16" around axis 4l, I can arrange the bow to be stationary and revolve the primary and secondary coils together with the iron body around theI bow. In this case 30 and 30" are the iron cores and 8' and 8" the yokes.

In order to reduce the generation of eddy current and-the warming up of the magnetic system where bow 39 cuts the magnetic lines of force in the slots 40. and 40", I can arrange these slots so as to cut the lines of force at a pointed angle instead of vertically. This is shown on Fig. 13. Like numerals indicate like parts on Figs. 12 and 13. 'Ihe inclined slots are designated by 43 and 43". The conductor connecting collectors 16 and 16" must, of course, also have inclined parts 39' and 39" to tit into the slots 43 and 43". Both parts are shown as being connected in the center by anannularrpart 44 carried by and insulated from the annular carrier or hub 45 which is keyed to the shaft 46. If the system is operated so that bow 43 is rotated, the rotation is accomplished by rotating shaft 46 which revolves in the bearing parts 47. Otherwise shaft 46 and bow 39 are stationary and the magnet systems together with primary coils 3' and 3" and secondary coils 1' and 2 mounted to the insulating cylinders 10' and 10" are revolved around shaft 46.

'I'he embodiment of my invention illustrated by Figs. l2 and 13 and described in the foregoing paragraph lends itself particularly Well to the control of multiphase current. If, for instance, three systems of primary coils and secondary coils having a common but each coil having an independent iron body are interconnected as per diagram of connections Fig. 14, three phase current can be regulated. In Fig. 14, 48, 49 and 50 illustrate the three phases of the primary system, each phase being connected to a primary coil 3', 3" and 3"' and influencing the regulating coil couples 1-2', 1--2" and d1"2"; the magnetic lines of force are illustrated by the loops 37, 38 and 51; the secondary coil pairs are interconnected by collectors 16', 16" and 16" and conductor 39"' which is the neutral point of the secondary windings. Each pair of secondary coils is electrically connected to one of the phases of the secondary three phase system 52, 53, 54.

Figs. 15 and 16 illustrate a regulating transformer according to my inventori for comparatively small tensions and capacity and having only one pair of coils. 57 are the spiral secondary coils, 58 the insulation between the individual turns of the coils, 58 acting at the same time as guides for collector brushes 59. Collector 59 is conductively and movably linked to arm 60 by connecting piece 61 which may be a flexible cable. Arm 60 is connected to shaft 56 which is located in the bore 65 of magnet core 63 and is revolvably carried in bearings 62. If the iron core 63 has the same potential as the collector 59, arm 60 moving in the annular opening 64 need not be insulated and the air space can be small; in this case bearings 62 need not be insulated from the iron core. The current collected from coils 57 by brushes 59 is conducted through 61, 60, 56 to a slip ring 66 and therefrom by collector brush 67 to terminal 68. 69 is the other terminal of the secondary system and is directly electrically connected with coils 57. 70 are the primary coils. 'I'he location of collector 59 in the extreme operating conditions is shown by dotted lines 71 and 72 in Fig. 16. This figure also shows the magnet core 63 and the magnet yokes 73 in section.

Figs. 17, 18 and 19 illustrate a transformer according to my invention which requires very little space. The spirally wound primary coils are interspersed between the spirally wound secondary coils 75. While in the arrangement as per Fig. 17 the individual primary coils 74 are pairwise and embedded side by side in the insulation material 76 between the individual turns of spiral coilY 74, they can also be arranged within each other and insulated from one another and in between spiral coil as illustrated by Fig. 18 on which the primary coils are designated by numeral 77. It is obvious that, aside from requiring little space, leakage voltage is much reduced by this arrangement. The tension of the primary coils arranged between two secondary coils can be an even multiple of the tension of the secondary coils if the primary coils are connected in series. The electric connections are illustrated by the diagram of connections Fig. 19. 78 and 79 are the terminals of secondary coils 75; 80 and 81 are the terminals of the four primary coils 74 which are connected in series. 82 are the contact rollers and 84 is the flexible conductor.

The design of contact rollers 82 which are provided with rims 83 and are guided by secondary spiral coils 75 is more particularly shown in Fig. 17.` Secondary coils 75 project from insulation matter 76 in order to constitute a rail-like guide for rollers 82. These projections further serve as radiators and reduce the temperature of the coils. For the latter purpose the secondary coils may be arranged to project on both sides of the insulation as illustrated in Fig. 18.

It is advantageous to arrange the regulating collectors so that the direction of the current ilow in one of the two brushes pertaining to one collector is opposite to the direction of flow in the other brush pertaining to the same collector; through this arrangement the contact pressure is increased by the electro-dynamic power action, particularly when negotiating overcurrents. The contact friction is greatly reduced by using contact rollers provided with wheel flanges as shown in Fig. 17.

While I believe the above described embodiments of my invention to be preferred embodiments, I wish it to be understood that I do not desire to be limited to the exact details of process, design and construction shown and described, for obvious modifications will occur to a person skilled in the art.

What I claim is:

l. A voltage regulating transformer having at least two independent coils concentrically located within one another, at least one of said coils having spiral conguration, and an insulating cylinder and insulated bolts radial with respect to said cylinder and adapted to rigidly hold said coil having spiral configuration to said cylinder.

2. A voltage regulating transformer consisting of at least tw'o' sets of independent electrically conductive windings concentrically ,located within one another, one of said sets consisting of at between each two coils pertaining to one pair.

4. A voltage regulating transformer consisting of at least two sets of independent electrically conductive windings concentrically located within one another, one of said sets consisting oiat least one pair of coils wound spirally and coaxially with respect to the other of saidA sets of windings, the two coils pertaining to one pair being located side. by side, said spirally wound coils consisting of a strip of bare metal, and a collector located between each two coils pertaining to one pair and -being adapted to be circumferentially and electrically conductively carried along said bare strip of metal.

5. A voltage' regulating transformer consisting 'of at least two sets of independent electrically conductive windings concentrically located within one another, one of said sets consisting of at least one pair of coils wound spirally and co-axially with respect tothe other of said sets of windings, the two coils pertaining to one pair being located side by side and being electrically connected in parallel.

6. A voltage regulating transformer consisting of at least two sets of independent electrically conductive windings, one of said windings consisting of at least one pair of coils, each of said coils consisting of a plurality of turns of a bare strip of metal spirally wound in one plane and co-axial with said other coil, insulating material between said individual turns, said insulating material projecting over said bare strip of metal, and a collector located between two of said coils pertaining to one pair and adapted to be conductively, circumferentially and radially carried along said bare strip of metal, said projecting insulating material forming a guide for said collector.

'7. Avoltage regulating transformer consisting of two sets of independent and electrically conductive windings concentrically located within one another, one of said sets consisting of a plurality of pairs of coils wound spirally and coaxiallx with respect to the other of said sets of windings, the two coils pertaining to one pair being located side by side, and all of saidpairs of coils being electrically connected in parallel.

8. A voltage regulating transformer consisting of at least two sets of independent electrically conductive windings concentrically located within one another, one of said sets consisting of at least one pair of coils wound spirally and coaxially with respect to the other of said lsets of windings, the two coils pertaining to one pair being located side by side, said spirally wound coils consisting of a strip of bare metal, and a collector located between the two coils pertaining to one pair, and provisions adapted to rotate said spirally wound coils around their axes thereby changing their position with respect to said collector.

9. A voltage regulating transformer consisting of a set oi' regulating coils and non-regulating coils having an axis in common with said regulating coils, said set of regulating coils consisting of a plurality of pairs of coils wound spirally and in a plane perpendicular to Asaid axis, each pair of regulating coils being provided with a regulating collector, all of said collectors being mechanically and electrically interconnected.

10. A voltage regulating transformer consisting of a set of regulating and non-regulating coils having an axis in common with said regulating coils, said set of regulating coils consisting 4oi! at least one pair of coils consisting of a plurality of turns wound spirally and in a plane perpendicular to said axis, each pair of regulating coils being provided with a regulating collector, a connecting part, links movably and conductively connecting said connecting part and said collector, and means for circumferentially varying the relative positions of said collector and said spirally wound coils thereby moving the collector in a radial direction and varying the number of said turns in operation and regulating the voltage.

l1` A voltage regulating transformer substantially consisting of an even number of sets of coils having a common axis, each set consisting of a plurality of independent co-axial coils wound spirally and within one another, one part of said coils pertaining to one set constituting the primary windings of the transformer and the other part constituting the regulating windings, said regulating windings projecting sidewards over said primary windings.

l2. A voltage regulating transformer substantially consisting of an even number of sets of coils having a common axis, each set consisting of a pluralityof independent co-axial coils wound spirally and within one another, one part of said coils pertaining to one set constituting the primary windings of the transformer and the other part constituting the regulating windings, said regulating windings projecting sidewards over said primary windings, and a collector located between each two of said sets of windings and being provided with contact rollers having wheel flanges cooperating with and guided by said proj ecting regulating windings.

13. A voltage regulating transformer consisting substantially of two groups of independent coils having a common axis, the two groups being located concentrically within one another, said coils individually vconsisting of a plurality of spiral windings, said windings being located in planes` perpendicular to the common axis of said coils, the spiral windings associated with one group being interspersed between and parallel to the spiral windings associated with another group.

AUGUST MEYERHANS. 

